Before de middwe of de 19f century, powitics in de United Kingdom was dominated by de Whigs and de Tories. These were not powiticaw parties in de modern sense but somewhat woose awwiances of interests and individuaws. The Whigs incwuded many of de weading aristocratic dynasties committed to de Protestant succession, and water drew support from ewements of de emerging industriaw interests and weawdy merchants, whiwe de Tories were associated wif de wanded gentry, de Church of Engwand and de Church of Scotwand.

By de mid 19f century, de Tories had evowved into de Conservative Party, and de Whigs had evowved into de Liberaw Party. The concept of right and weft came originawwy from France, where de supporters of a monarchy (constitutionaw or absowute) sat on de right wing of de Nationaw Assembwy, and repubwicans on de weft. In de wate 19f century de Liberaw Party began to wean towards de weft. Liberaw Unionists spwit off from de Liberaws over Irish Home Ruwe and moved cwoser to de Conservatives over time.

The Liberaws and Conservatives dominated de powiticaw scene untiw de 1920s, when de Liberaw Party decwined in popuwarity and suffered a wong stream of resignations. It was repwaced as de main anti-Tory opposition party by de newwy emerging Labour Party, which represented an awwiance between de wabour movement, organised trades unions and various sociawist societies.

Since den de Conservative and Labour parties have dominated British powitics, and have awternated in government ever since. However, de UK is not qwite a two-party system as oder parties have significant support. The Liberaw Democrats were de dird wargest party untiw de 2015 generaw ewection when dey were overtaken by de Scottish Nationaw Party in terms of seats and UK powiticaw party membership, and by de UK Independence Party in terms of votes.